NASA, Department of Energy testing ‘Kilopower’ space nuclear reactor

In preparing for possible missions to the Red Planet in the near future, NASA’s Space Technology Mission Directorate (STMD) has been given the go-ahead to test a small nuclear reactor that could one day run equipment on the Martian surface.

The Kilopower project is working to advance a design for a compact, low-cost, and scalable nuclear fission power system for missions that require lots of power, such as a human mission to Mars. The technology uses a fission reactor with a uranium-235 reactor core to generate heat, which is then transferred via passive sodium heat pipes to Stirling engines. Those engines use that heat to create pressure, which moves a piston – much as old coal-powered ships used steam pressure to run their pistons. When coupled to an alternator, the Stirling engine produces electricity.

“What we are striving to do is give space missions an option beyond RTGs [radioisotope thermoelectric generators], which generally provide a couple hundred watts or so,” Lee Mason, STMD’s principal technologist for Power and Energy Storage at NASA Headquarters in Washington, D.C., said in a NASA news release. “The big difference between all the great things we’ve done on Mars, and what we would need to do for a human mission to that planet, is power.”

Mason said the new technology could provide kilowatts of power and even be upgraded to provide hundreds of kilowatts or even megawatts of power.

“We call it the Kilopower project because it gives us a near-term option to provide kilowatts for missions that previously were constrained to use less,” Mason said. “But first things first, and our test program is the way to get started.”